Upon any person engaging or continuing within this City in any public service or utility business, except railroad car, express, pipeline, telephone and telegraph companies, water carriers by steamboat or steamship and motor carriers, there is likewise hereby levied and shall be collected, taxes on account of the business engaged in equal to the gross income of the business multiplied by the respective rates, as follows: Bus companies, two percent (2%); Water Companies, four percent (4%); Electric Light and Power Companies - sales and demand charges domestic purposes and commercial lighting, four percent (4%); all other sales and demand charges, three percent (3%); Natural gas companies, three percent (3%) of the gross income, said gross income for this purpose to be determined by deducting from gross income from all sales of gas to consumers the amount of the tax paid by the taxpayer under Section 757.09 upon the production of the same gas; and upon all other public service or utility business, two percent (2%).